Cody Arlie ReedResearch + data
WorkHow does racial segregation change over a day?

Time + exposure

How does racial segregation change over a day?

ProblemResidential measures fix people at home, even though daily movement changes who shares urban space.

What I builtI linked pre-COVID mobile-device location data to Census data, reweighted the sample toward population composition, and estimated segregation by hour across 18 U.S. commuting zones.

OwnershipSole researcher and developer: study design, data engineering, statistical modeling, visualization, and writing

Result

Segregation was lower during weekday working hours; in 13 of 18 regions, even the highest estimate remained below residential segregation.

Thirteen of 18 regions stayed below residential segregation even at their highest dynamic estimate, and 17 fell below half the residential benchmark at their low
Dynamic and residential racial segregation across the day

What I built

Link mobile-device locations to population data, then estimate segregation by hour.

  1. 01
    Infer home

    Cluster nighttime locations to infer home areas, then link each area to Census population characteristics.

  2. 02
    Reweight the sample

    Align the device sample with Census population composition.

  3. 03
    Compute at scale

    Calculate distance weights and the multigroup Theil segregation measure in compiled C++ called from R.

  4. 04
    Aggregate by hour

    Estimate segregation for 428 hourly intervals in each of 18 commuting zones—regional labor markets defined by commuting patterns.

Compared with residential segregation

Daily mobility reduced segregation relative to residential measures in most regions.

Residential segregation uses where people live; the hourly estimates incorporate where people spend time throughout the day.

In 13 of 18 commuting zones, even the highest dynamic-segregation estimate remained below the residential benchmark.

17 of 18fell below half the residential benchmark at the daily low
13 of 18stayed below the residential benchmark even at their highest estimate
Friday + Saturdaywere the least-segregated nights of the week